Fatal error: Uncaught Error: Class "Drupal\FunctionalJavascriptTests\WebDriverTestBase" not found in /home/www/drupal8/test/core/tests/Drupal/FunctionalJavascriptTests/Core/Session/SessionTest.php:13
Stack trace:
#0 {main}
thrown in /home/www/drupal8/test/core/tests/Drupal/FunctionalJavascriptTests/Core/Session/SessionTest.php on line 13